0.5.0 is a major refactoring of the 0.4.0 branch
A short summary:

* New dependency on feedparser and chardet.
* Global and per-feed filters implemented.
* Hooks, to call code on events (like new items, changing selection, etc.)
* Entirely changed, much less fragile on-disk format.
* Canto and canto-fetch are now a single, multi-call binary
* Canto-fetch no longer has its own config
* More useful keybinds, support lists of actions and arbitrary functions.
* Per-feed renderers can be configured.
* Story items now include all content, rather than just title/link/description
    (pretty useful for neat per-feed renderers, thanks to feedparser)
* Reader is now prettier, and more correct.
* Canto.extra is provided for nice helper functions for your config.
* Code documentation is much improved
* Code organization is more logical
* Proper locking between multiple instances of canto/canto-fetch.
* Entirely backwards compatible with 0.4.0 configs